The present invention relates in general to delivery of mobile to mobile text messages, and, more specifically, to use of a dit-dah code to send text messages over a non-signaling channel of a cellular wireless network.
The Short Message Service (SMS) was introduced to allow cell phone subscribers to exchange text messages between handsets. Instead of using a direct connection between handsets, the signaling or control channel of the cellular network has been used for transporting the text messages. The signaling channel connects to an SS7 network within the core network of the cellular provider that monitors handset locations and routes call signaling messages for establishing and terminating voice calls.
To avoid congestion, a limit of 160 characters was imposed on SMS text messages by the relevant IS-41 standard because the signaling channel and the other portions of the service provider's SS7 network typically have a limited extra capacity for devoting to SMS. Due to the popularity of the SMS service, the sending and receiving of text messages has nevertheless become a burden on the SS7 network which results in delays in both call processing and text message delivery. Thus, it would be desirable to remove message delivery delays, eliminate the character length limit, and avoid congestion in the SS7 network and the signaling channel.
Manual SMS text creation on conventional handsets is relatively inefficient. Text entry is usually performed using triple-tap sequences on the alpha-numeric keys on a handset or by tapping individual letter keys on a miniature keyboard (if so equipped). The small size of the keys on a handset makes text entry slower and requires the user to look at the keypad during a text entry. In competitions between Morse code operators and the fastest phone text messengers, Morse code has been shown to be faster and more efficient. Thus, it would be desirable to facilitate a faster and more efficient method of text entry for users who know or are willing to learn Morse code or similar methods of text entry.
Conventional SMS is also relatively inefficient in terms of transmission bandwidth utilization. Data packets sent via the signaling channel include ASCII code representation of the text. The ASCII encoding and the digital transport methods used in the signaling channel provide low error rates but are wasteful of channel capacity compared to other forms of encoding.